Check out the Trac to see the state of development. There are three core developers with commit privileges they do all the work – mostly – and they work on a voluntary basis as this an OS project, members also help to move it forward and the speed at which it does develop is largely governed by the effort we all put in and other than the main three developers not many of us are contributing at the moment!

As for themes ? what do you want, again these are written on a voluntary basis and themes for BP are of a magnitude harder than a bog standard WP layout and are not a trivial matter and take time, but there are themes around if you look.